This invention relates to automatic yarn sampling devices. More particularly, this invention relates to an automatic yarn sampling device which is operable up to yarn processing speeds of at least 1000 meters/minute and which exerts significantly less tension on the yarn than that tension typically required to approach the deformation yield point of partially oriented yarn.
In addition to fully drawn yarn, fiber manufacturers often manufacture multifilament yarn which is partially, rather than fully, oriented before being wound upon a spool. A process for manufacturing partially oriented yarn is described in D. Petrille, "Drawing And Bulking Polyester Yarns," U.S. Pat. No. 3,771,307 (Nov. 13, 1973).
It is usually desirable to sample spools of multifilament yarn to test various properties for quality control purposes before the yarn is subjected to further processing. Accurate measurement of the degree of orientation is a particularly important quality control check for partially oriented multifilament yarn.
For some time there has been a need in the industry for an automatic yarn sampler which would not exert significant tension or stress on the yarn to be sampled. Various types of automatic yarn samplers have been developed by prior artisans, which utilize automatic knotters and air splicers, but these devices either cannot operate at normal yarn testing speeds or subject the yarn being sampled to tension in excess of the typical yarn deformation tension range of partially oriented yarn. This tension exerted on partially oriented multifilament yarn during the sampling process prior to measurement virtually precludes accurate measurement of many yarn properties, since the sampling tension causes permanent deformation of the yarn sample.